Heretofore, in the semiconductor device, for example, as a transistor, a thin film transistor using amorphous silicon, polycrystal silicon or the like has been utilized. Recently, focus of attention has been placed on zinc oxide (ZnO) to be used as a thin film material for manufacturing the semiconductor device. Not only an ultraviolet ray emission device, a transparent transistor, and so on, have replaced the existing application as photo-electron devices, but also totally new applications have been developed. Currently, for manufacturing a light emission device or a transistor using ZnO, a sapphire substrate is used.
In addition, heretofore, for manufacturing the semiconductor device, the formation of a high quality thin film on the substrate has been much requested. The following factors may conceivably determine the quality of thin film crystallinity (coherency):                (a) grain size;        (b) fluctuation of lattice plane spacing (distortion; and        (c) fluctuation of lattice plane direction orientation, mosaicness).Generally, a high quality crystal is characterized by (a) a large grain size, (b) small fluctuation of lattice plane spacing, and (c) small mosaicness.        